Audit Vehicle and Audit Method for Remote Emissions Sensing FIELD OF THE INVENTION [0001] The present invention relates generally to systems and methods for
auditing the performance of remote (also called open path) vehicle emissions sensing
systems. More specifically, the present invention relates to an audit vehicle and audit
method that can be used to drive through a remote vehicle emissions sensing system
whole releasing a known quantity and mixture of gas to test the performance of the
sensing system.
BACKGROUND OF THE INVENTION [0002] Systems are known in the art for detecting the tail pipe emissions or
exhaust plumes of the vehicles as they drive on a vehicle path such as a roadway. For
example, it is known for a light beam to be projected across the roadway and received by
a receiver that analyzes the received light and determines the components of the vehicles emissions. In order to test the performance of such systems, it is desirable to have a
vehicle that emits known volumes, mixtures, and concentrations of gases and that can be
driven through the sensing system in order to test the detection performance of the
system.
SUMMARY OF THE INVENTION [0003] It is therefore a feature and advantage of the present invention to
provide a vehicle that emits known volumes, mixtures, and concentrations of gases and
that can be driven through the system in order to test the detection performance of the
system.
[0004] It is another feature and advantage of the present invention to provide
a method for testing or auditing vehicle emissions sensing systems.
[0005] The above and other features and advantages are achieved through the
use of a novel apparatus and method as herein disclosed. In accordance with one
embodiment of the present invention, an apparatus for dispensing gas from a vehicle has
a plurality of compressed gas cylinders filled with known concentrations of gases,
referred to also as "gas bottles"; a plurality of shutoff valves, one valve associated with
each of the gas bottle for controlling gas flow out of that gas bottle; a manifold that
receives gas from each of the shutoff valves and leads to a single pressure regulator; an
output gas line leading from the pressure regulator; a mster shutoff valve that controls the
release of the audit gas; and a sample gas outlet opening at the end of the output line with flow through the output line measured.
[0006] In accordance with another embodiment of the present invention, a
system for recording telemetry data associated with a remote emissions audit vehicle,
includes: a central computer; and at least one telemetry sensing device comprising at least one of: a vehicle speed sensor mounted at a non-drive wheel; a global positioning system
sensor; ambient atmospheric condition sensors; an infrared beam detector; and an output gas flow rate sensor. Data from at least one sensing device is stored by the computer.
[0007] In accordance with another embodiment of the present invention, a
method for recording data related to the telemetry of an audit vehicle is provided. The
method includes driving the audit vehicle past a remote emissions sensor while emitting
a sample blend gas; and recording telemetry data relating to the audit vehicle. The telemetry data includes at least one of: vehicle speed read by a sensor on a non-drive
wheel, GPS information, atmospheric information, IR light information, road temperature
sensing information, and gas flow rate information.
[0008] In another embodiment of the present invention, a method of
controlling gases emitted by an audit vehicle, includes controlling a plurality of operated
valves each associated with a bottle; driving the audit vehicle past a remote sensing
device; and recording data related to the audit path.
[0009] There has thus been outlined, rather broadly, the more important
features of the invention in order that the detailed description thereof that follows may
be better understood, and in order that the present contribution to the art may be better
appreciated. There are, of course, additional features of the invention that will be
described below and which will form the subject matter of the claims appended hereto.
[0010] In this respect, before explaining at least one embodiment of the
invention in detail, it is to be understood that the invention is not limited in its application
to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other
embodiments and of being practiced and carried out in various ways. Also, it is to be
understood that the pliraseology and terminology employed herein, as well as the abstract,
are for the purpose of description and should not be regarded as limiting.
[0011] As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing
of other structures, methods and systems for carrying out the several purposes of the
present invention. It is important, therefore, that the claims be regarded as including such
equivalent constructions insofar as they do not depart from the spirit and scope of the
present invention.
BRIEF DESCRIPTION OF THE DRAWINGS [0012] FIG. 1 is a partial respective view of a truck bed having a rack for
housing sample gas bottles.
[0013] FIG. 2 is a perspective view of a rack holding sample gas bottles and
a gas distribution system according to a preferred embodiment of the present invention.
[0014] FIG. 3 is a schematic diagram illustrating a central processing
computer and various peripheral devices that provide information to the computer.
[0015] FIG. 4 is a flow chart showing a series of steps that is performed during an audit sequence.
[0016] FIG. 5 is a flow chart showing various information that is monitored
and logged by the computer.
[0017] FIG. 6 is a flow chart that shows a method for tracking the gas
expended by an audit vehicle system.
DETAILED DESCRIPTION OF PREFERRED
EMBODIMENTS OF THE INVENTION [0018] A preferred embodiment of the present invention provides a vehicle
that emits known volumes mixtures and concentrations of gases and that can be driven through the system in order to test the detection performance of the system. A preferred
embodiment also provides a method for testing or auditing the performance of vehicle
emissions sensing systems.
[0019] A preferred embodiment of the present inventive apparatus and method
is illustrated in FIGS. 1 and 2. FIG. 1 depicts a bed in the rear portion of a vehicle 10
that may be used as the audit vehicle. A remote sensing (i.e., open-path sensing) device
2 receives a beam 4 and senses emission data when the beam 4 passes through an exhaust
gas plane. The audit vehicle 10 releases bottled gas blends, while its own exhaust is
diverted, to test the performance of the open path emissions sensor 2 that is sitting on the
side of the road. This method of auditing the open path emissions sensor 2 that sits on
the side of the road is best for emulating the entire process of a typical vehicle passing by the emissions sensor.
[0020] In a preferred embodiment, the audit vehicle 10 is a heavy duty pickup
truck that has sufficient payload performance to carry the necessary equipment used in
that embodiment. In the preferred embodiment, a rack 12 is provided to hold a number of compressed gas cylinders, also referred to as gas bottles 14, which in a preferred
embodiment, includes seven gas bottles. These gas bottles 14 can include any
appropriate number of different blends and may also include one bottle that is dedicated to a purge material (e.g. nitrogen) that can be released to purge the system of the blended gases. Each bottle contains one blend of gases. Thus, one bottle is used at a time. The
purging bottle is used between different blends, that is when switching from one blend
to another, to flush the system of any residual gases left over from the previously used
blend.
[0021] Turning to FIG. 2, in a preferred embodiment, the rack 12 holds the gas
bottles 14 as shown. Each gas bottle 14 has a primary valve 16 and outlet port as shown.
A check valve 17 is also provided at the output of each bottle 14 to prevent back filling
of the bottle. This check valve 17 is desirable, as it is possible for one of the bottles
connected to the manifold 20 to have a higher pressure, forcing a backfill until the
pressures in each bottle are the same. This backfill condition could occur if any of the
shutoff valves 18 were to remain open for more than one bottle at a time. A second check
valve 19 may be used between a shutoff valve 18 and the common gas manifold 20 as
an additional measure of assurance in not contaminating the contents of one gas blend
with another. Each gas bottle 14 has a line leading to a shutoff valve 18 as shown. In a
preferred embodiment, the shutoff valve 18 is a power driven ball valve. A plunger type
solenoid valve can also be used, however a ball valve provides a good ability to handle
high pressures, such as up to 2000 psi in the gas cylinders, and when opened ball valves do not restrict the gas flow. In the preferred embodiment the ball valves are motorized
and are controlled by a computer in the cab of the vehicle as described herein. However,
in other embodiments the valves 18 can be controlled by a switch in the cab or
alternatively a switch on the outside of the valve housing that can be operated by the user to open and close the valve.
[0022] An advantage of providing multiple ball valves 18, one for each tank 14, is that the operator does not have to detach and reattach a single valve each time the
operator desires to change from one bottle to another. That is, in the preferred embodiment illustrated in FIG. 2 with multiple valves 18, the operator needs only to
disconnect each bottle 14 from its associated line when it is time to change a bottle
because it has been expended. This feature provides an ability to change between blends (that is change between bottles) very quickly while on site. Thus, in an audit
environment, this reduces the time an operator spends outside the vehicle as compared
to having to connect and disconnect a single valve each time it is desired to change between bottles. This benefit is enhanced by control of the ball valves remotely from
inside the vehicle cab.
[0023] In normal use to output a test blend, only one of the valves 18 is open
at a time, and the others are closed. A manifold 20 leading from the shutoff valves 18
and secondary check valves 19 if equipped leads to an electronic pressure sensor that
leads to a pressure regulator 24 that can be set so that the test blend (or purge gas) is
output with a known pressure, hence providing a control of the flow volume.
Downstream from the pressure regulator 24 is master release valve 25, preferably another
motorized ball valve, which is used to activate gas flow through the remaining portion
of the gas distribution system. This valve 25 can also be controlled by a central computer
from inside the vehicle cab, or can manually be operated by a momentary remote switch
located in the audit vehicle's cab. After the master release valve 25, the gas passes
through a line 26 into a output pipe 27 that leads to an output opening 29. A venturi flow
sensor 28 is present in a portion of the output pipe 27. This flow sensor 28 measures the
flow of audit gases through the gas delivery system, by sensing the pressure differential
through a venturi restriction.
[0024] FIG. 3 schematically depicts the connection of, and communication between, various components of the audit vehicle 10. The audit vehicle 10 has a
computer 30, which may be a laptop computer. The computer 30 preferably runs scientific logging software as well as audit process controlling software. The computer
30 receives vehicle speed and acceleration measurements from a wheel speed sensor 32. In preferred embodiments, the wheel sensor is mounted to a non-drive wheel of the
vehicle, such as for example, a front wheel of a pickup truck having only the rear wheels driven. This is to potentially avoid variations in speed caused by the audit vehicle's
engine, though a drive wheel sensor could be used. A non-drive wheel is specified
primarily because systems that measure vehicle speed through an apparatus that is
attached to or monitors the speed of the driveshaft and related components has proven to
be inconsistent in reporting speed and especially change in speed (acceleration). For this
reason, a non-drive wheel is preferred, however data from a drive wheel, if the data is
measured from a speed sensing device at the wheel, should not be susceptible to engine
output variations, slop in the drive train, etc. that a driveshaft mounted speed measuring
system would encounter. In this case it is conceivable that data collected from even a
drive wheel should provide acceptable precision and accuracy of speed and change of
speed measurements. The sensor 32 can be an antilock brake wheel speed sensor. The
taking of data from a speed sensor on a front wheel has been found to have advantages
as compared to speed sensor that is mounted on a drive shaft because driven components
such as a drive shaft or differential are subject to speed fluctuations caused by the
vehicle's engine or loose tolerances in the various parts of the drive train. Non-drive
wheels have been found not to be subject to the same fluctuations, and hence to provide a truer and steady indication of actual vehicle speed. Speed information from the sensor
32 is fed into the central computer 30 and is monitored so that the speed at which the audit test was conducted can be verified upon later examination. Audit runs are to be
conducted within a range of speed, however the speed data will be used to audit any speed measuring devices that accompany the emissions sensor 2. The computer 30 also
calculates change in speed, i.e. acceleration, from information collected from the speed
sensor 32, and records this calculated acceleration along with the measured speed.
[0025] Also providing an input signal to the computer 30 is a GPS receiver 34. The GPS receiver 34 can provide positional data that is stored by the computer,
indicating the location at which the audit was performed. Further, GPS systems have
been found to have an ability to also provide an indication of vehicle speed. This
indication of vehicle speed can be used to compare with the wheel sensor data for sensor
32 to ensure accuracy. Further, the GPS system 34 also provides an indication of the date
and time at which testing takes place, which date and time information can be stored in
the central computer 30 along with other data records to show the location date and time
and speed at which test took place.
[0026] Also attached to the computer 30 is a weather module 36, for sensing
ambient condition via a pod of sensors 37. The ambient condition sensors 37 detect
ambient conditions such as outdoor temperature, relative humidity and/or dew point, and
barometric pressure when the audit test is performed. The sensors 37 can also record
road surface temperature. This information is stored by the central computer 30 and can
be used to ensure that testing is done within a prescribed condition range, or to adjust the
results based on ambient conditions if desired.
[0027] Accordingly, the central computer 30 can store a telemetry log which
includes e.g., location, vehicle speed, ambient conditions, read temperature and the date
and time for each test.
[0028] The computer 30 also receives data from an infrared (IR) pulse sensor 38 mounted on the outside of or underneath the vehicle. The remote emissions sensing
system 2 projects an infrared beam 4. As the vehicle 10 is driven past the sensing system during an audit run, the IR sensor 38 detects the beam (and correspondingly detects that
the vehicle has just passed the emissions sensor). The IR sensor 38 sends a pulse signal to the computer 30. This pulse signal indicates the referenced time at which the vehicle
passed the emissions sensor, and can be used for several purposes. First, the time of the
pulse is stored by the computer, and thus the computer can store the other telemetry data
corresponding to that time. Further, since the GPS unit 34 gathers date & time data
from potentially the same source as the remote emissions sensing system 2 (if equipped
with a GPS that supplies date & time among other information), the time clocks of both
the audit vehicle computer 30 and the remote emissions sensing system 2 will be
synchronized.
[0029] FIG. 3 also shows that the computer 30 can control thqshutoff valve 18
and master release valve 25. This permits the selection of gases from a remote location,
rather than the operator needing to manually turn valves or move components to the rear
of the vehicle. Of course, in other embodiments, the valves could be controlled remotely
in another fashion, or could be activated manually if necessary.
[0030] A power inverter 40 can be provided to take power from the audit
vehicle and invert from 12 volts DC to 110 volts AC it so that it is compatible with any
of the pieces of the equipment, such as computer 30, GPS 34, and weather monitor 36 as
necessary.
[0031] The computer 30 also receives information from a flow rate detector in the output pipe 27 and from a pressure transducer mounted in the gas manifold 22.
The detector is a venturi gas flow measurement system 28 that provides gas flow measurements to an adequate degree of precision and accuracy^ The flow detector 28 can
be used for test accuracy and also to indicate when a gas bottle is nearly empty. The
pressure transducer 22 supplies data logged by the computer 30 regarding delivery pressure to the master release valve 25 and can be cross-verified with the pressure gage
on the mater regulator 24.
[0032] The computer 30 can also receive data from a vehicle's standard on¬
board diagnostic system (e.g., OBD), if such data is desired. The OBD system can
provide engine RPM, load on engine, and other parameters useful in quality assuring the
information gathered from speed sensor 32 and measured weather parameters gathered
by the weather module 36.
[0033] FIG. 4 is a flow chart that depicts an overall audit process. At step 101,
the user decides to initiate an audit. At step 102, the user verifies that the audit vehicle
is road worthy by visually and otherwise checking the vehicle systems. This includes
verifying that the audit vehicle has enough fuel to complete the day's auditing activities.
At step 103, the user verifies that the audit vehicle has the appropriate gases and records
identifying information, such as gas cylinder serial number and certified concentrations,
in a special auditing log or in an electronic log contained within computer 30..
[0034] At step 104, the user connects exhaust diversion plumbing on the
vehicle. In a preferred embodiment of the vehicle 10, the vehicle 10 is a conventional
vehicle pickup truck, which has an exhaust diverting device mounted to it. The exhaust diverting device is .a vertical stack that has an sufficiently high so that it will not interfere
with measurement of an sample gas plume near the ground. The diverting device connects to the vehicle's exhaust system, sending the exhaust gases high above the roofline of the vehicle to assure that audit vehicle's exhaust gases do not contaminate the gases being released out the output pipe 29 from the audit gas bottles 14. A second,
dummy tail pipe, which comprises the outlet pipe 27, flow measurement system 28, and outlet 29, is also mounted to the lower rear of the vehicle and it is from where the audit
gases are released during an audit run.
[0035] At step 105 the operator verifies the location where the open path
emissions sensor 2 is sited. At step 106, the operator travels to the audit site. At step
107, the operator verifies that the open path emission sensor 2 is at the audit site. At step
108, the operator activates a power inverter, which powers equipment such as for example, the computer 30. At step 109, the operator activates the on board computer 30
and its associated telemetry sensing devices 22, 34, 36, 38 and 28. At step 110 the
operator logs the computer 30 into a telemetry software application. At step 111, the
operator insures that the computer 30 is using the correct date and time which may be
provided from the GPS unit 34. At step 112, the operator conducts an intercomparison
between the audit vehicle's weather measuring equipment and the on site equipment
located within or near the open path emissions sensor 2. GPS location data 34 should
also be compered with that in the emissions sensor 2. At step 113, the operator sets
and/or checks the height of the infrared (IR) beam detector 38 that senses the IR source of the emissions sensor's 2 optical path 4, which will trigger the IR detector 38 to identify
the exact time at which the vehicle passes the open path sensing equipment. At step 114,
the operator opens the primary valves 16 of each bottle. At step 115, the operator
activates each of the shutoff valves 18 and master release valve 25 and verifies that gas
delivery is occurring at a proper flow. The bottle of purge gas is preferably left to last in the sequence of checking the delivery of gases so that the entire gas delivery system is
purges of any concentrations of audit gases. At step 117, the operator verifies that the computer 30 is gathering telemetry data. At step 118, the operator makes two to four
audit passes with the vehicle expending no gas. This is done to verify that the audit
vehicle's engine emissions are properly diverted high over the emissions sensor 2 optical
path 4. At step 119, the operator checks if the emissions sensor 2 is reading emissions even though no audit gas was passed. If so, at step 120, the operator aborts the audit
process because there will be contamination of audit gases by the audit vehicle's own
emissions. At step 121, the operator sets a traffic cone to indicate an intended gas release
start point. This provides for a consistent point of release of the audit gases by the master
release valve 25. At step 122, the operator conducts a required number of audit passes
to perform an audit.
[0036] At step 123 the operator logs the computer 30 out of the audit
application. At step 124, the operator deactivates the telemetry devices 22, 34, 36, 38 and
28. At step 125, the operator deactivates the power inverter 40 to avoid running down
the battery in the audit vehicle. At step 126, the operator closes all gas bottles by closing
each primary valve 16 to avoid leakage. At step 127 the operator returns the audit vehicle
10 to its storage location. At step 128, the operator can remove and/or replace any
expended gas bottles 14. At step 129 the operator cah record observations and complete
an audit report including telemetry information from the computer 30 and emissions data
read by the emissions sensor 2 if available at the end of the auditing activities.
[0037] FIG. 5 is a flow chart depicting various information processed by the telemetry system in the computer 30. The software application is initiated at step 200,
and the date and time is initialized at step 202 from the GPS 34. Then, at step 204 the system monitors and logs the parameters including e.g., ambient temperature 212, relative humidity 214, barometric pressure 216 from weather module 36 and pod of sensors 37. Latitude and longitude 206, speed and heading 208 data are gathered from the GPS unit
34., The telemetry system also records a pulse 222 when the infrared sensor 38 senses the
sample path 4 of the emissions sensor 2. Audit gas flow rate 218 from gas flow sensor 28, and the gas manifold pressure 220 collected from the pressure transducer 22 in the
gas manifold 20 are recorded regardless of whether audit gas is released. The computer
30 calculates acceleration 211 from a change in vehicle speed 210 measured by the wheel
sensor 32.
[0038] FIG. 6 shows a feature of a preferred embodiment the invention that
tracks gas usage process when initialized in step 300. The system measures the audit gas
flow 302 via the gas flow sensor 28. The system calculates the amount of gas expended
from each bottle at step 304 in the computer 30 and calculates the remaining amount of gas at step 306. At step 308, if the remaining gas is less than a predetermined value, the system warns the user of a low gas level at 310, or informs the user of the amount of gas remaining at step 312, if the remaining gas is more than the predetermined value'. This system is effective in tracking the amount of remaining audit gas left in cylinders 14, because the amount of gas originally loaded into the cylinders is provided by the vendor of the gases. The original amount of gas must be entered into the computer 30 in order for accurate gas usage information to be available.
[0039] The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.